1. Field of the Invention
The invention concerns an agent for stabilizing foodstuffs and cosmetic agents as well as a process for production thereof.
Lipid-rich foodstuffs and cosmetic agents can become rancid in particular as a result of a lipid-peroxidation processes (autooxidation). The rancidification of foodstuffs (frequently recognized by their prickly, unpleasant taste) and cosmetic agents results in their becoming unusable.
2. Description of the Related Art
It is already known to add natural or synthetic antioxidants to foodstuffs and cosmetic agents in order to inhibit their autooxidation. Typical anitoxidants are, for example, tert-butylmethoxyphenol (tert-butylhydroxyanisol, BHA) and di-tert-butylmethylphenol (Butylhydroxy-toluol, BHT), ester of gallic acid, tocopherol (vitamin E) as well as ascorbic acid and their fat soluble esters. There is however a great demand for further antioxidants, and in particular for those which can be added to foodstuffs, without having the legal character of a listed food additive which requires regulatory approval.
It was the task of the present invention to provide an antioxidant which is in particularly suitable for stabilizing lipid-rich foodstuffs.
This task is inventively solved by the provision of an antioxidation effective extract, wherein the extract can be produced by extracting non-enzymatically browned grain germs, or a mixture containing non-enzymatically browned grain germs, using a solvent or solvent mixture having an ETN-value ranging from 0.6 to 0.8 and optionally separating off the extraction agent.
For ETN-value and its determination, see Christian Riechhardt, Chem. Rev. 1994, 2319-2358.
The grain germs are preferably separated from the chaff of the grains in conventional manner prior to roasting, in particular separated from the cortex, the epidermis (seed cover, bran), the endosperm (starch and gluten) and the aleurone layer, since these residual components take up a large volume in comparison to the germ and thereby raise the cost of the roasting process.
In accordance with a suitable process according to the invention for production of an antioxidative effective extract, non-enzymatic browned grain germs or a mixture, which includes non-enzymatic browned grain germs, are extracted with a solvent or solvent mixture having a ETN-value between 0.6 and 0.8 and optionally separating the extracting agent.
The extracts obtained with such a polar extraction agent, for example with ethanol or an ethanol solution, are surprisingly suitable for stabilization of lipid-rich foodstuffs as compared to extracts which were obtained with extraction agents of lower polarity (such as for example acetone or diethyl ether). This could not be predicted a priori since it is known that polar extraction solvent agents first extract polar contents from the respective material being extracted, and polar substances were generally considered to be unsuitable for the stabilization of lipid-rich foodstuffs on the basis of their low fat solubility.
The grain germ (Poacae,=Graminaceae) extracted in accordance with the invention are preferably wheat, barley or other germ from grains from the subfamily of Pooideae; also corn germ and other germ of the corresponding other grain subfamilies can be employed with good success.
The non-enzymatic browning typically occurs by roasting, and this preferably under the action of dry heat at a temperature of preferably between 50 and 200xc2x0 C.; roasting temperatures in the range between 120 and 170xc2x0 C. are preferred and particularly preferred are roasting temperatures of between 140 and 160xc2x0 C. An increase in the roasting temperature generally brings about, in the mentioned temperature ranges, an improvement in the antioxidative effect of the corresponding extract (see Example 10 below). With an increase in the roasting temperature above 160xc2x0 C., however, no significant improvement in the antioxidative effect is achieved any longer. At roasting temperatures below approximately 160-170xc2x0 C. only insignificant amountsxe2x80x94if anyxe2x80x94of toxic by-products or minor constituents are formed, while at higher temperatures considerable amounts of these substances could result.
Roasting is preferably carried out for 5-100 minutes.
During browning, products of the Maillard reaction are formed, and it has now been accomplished, by extraction with the mentioned solvents or solvent mixtures, to obtain a corresponding extract which possess a surprisingly high antioxidative effectiveness. Control tests have surprisingly shown that fractionations of this (total) extract do not result in substance compositions which possess an improved antioxidation effectiveness in comparison to the untreated (total) extract, but rather that the obtained (total) extract itself possess the highest effectiveness. This can be traced back to a surprisingly synergistic effect of the extract component substances.
Even though a fractionation does not lead to an improvement in the antioxidative properties of the inventive extract, it is however sometimes useful to separate out the aroma and/or color forming minor constituents of the extract. For this, the person of ordinary skill in the art can use the conventional separation processes.
In accordance with a further aspect, the invention includes in general the use of extracts of non-enzymatically browned grain germ as antioxidative effective agents for stabilization of foodstuffs, in particular lipid-rich foodstuffs or cosmetic agents, wherein for production of the extracts any solvents or solvent mixtures, in particular those which are liquid at room temperature (20-25xc2x0 C.), can be employed as extraction agents.
However, particularly suitable for use as antioxidants are the extracts in accordance with the invention, in which an extraction agent, particularly from the ethanol including group of the dipolar protic solvent agents, is employed in their production, and in particular one with an ETN-value between approximately 0.6 (1-propanol) and approximately 0.8 (glycol). These (polar) extracts are surprisingly not inferior to the conventional synthetic antioxidants, and in certain respects are even superior to them.
The invention concerns also foodstuffs and cosmetic agents, which include a stabilizing effective amount of the inventive extract or a fraction of such an extract.
The extracts according to the invention are particularly suitable for stabilizing lipid-rich foodstuffs such as pure conventional plant oils (for example corn oil) or complex, sensitive foodstuffs (such as, for example, unbrowned wheat germ itself). For example, unbrowned wheat germ can be stabilized by roasting a small portion of the wheat germ, extracting the roasted wheat germ with ethanol, and applying the extract to the unbrowned wheat germ.
It has surprisingly however been found within the framework of the invention, that for stabilization of unbrowned grain germ it is not only the inventive extract, but rather also non-enzymatic browned grain germ itself, that can be employed, wherein the unbrowned grain germ is mixed with the non-enzymatically browned grain germ. Herein preferably the ratio of the non-enzymatic browned to the unbrowned grain germ is adjusted to a mass mixing ratio in a range of from 2:100 to 8:100, preferably however from 2:100 to 4:100.